1. Field
Embodiments described herein relate generally to a phase locked loop circuit.
2. Background Art
A conventional phase locked loop circuit (PLL circuit) converts a digital code into an analog value of current or the like by means of a D/A converter (Digital-to-Analog Converter: DAC) and controls an oscillatory frequency according to the analog value.
Such a conventional phase locked loop circuit may cause a transitional overcurrent (glitch) at the moment of switching of the digital codes of a DAC, temporarily increasing an oscillatory frequency error. In this case, such a phase locked loop circuit is unusable in a system complying with exacting specifications about oscillatory frequency errors.
Moreover, the conventional phase locked loop circuit includes, for example, a filter inserted into the current path of a DAC to suppress the glitch. However, this configuration increases the circuit area of the phase locked loop circuit.